Bags



ug 2, 1966 T, B. LUDLOW ETAL1 3,263,902

BAGS

Filed Jan. 28, 1965 5 Sheets-Sheet 1 FIGB.

Aug. 2, w66 T. B. LUDLOW ETAL.

BAGS

5 Sheets-Sheet 2 Filed Jan. 28, 1965 Aug- 2, i966 T. E. LUDLOW ETAL 3,263,902

BAGS

5 Sheets-Sheet 3 Filed Jan'. 28, 1965 United States Patent 3,263,902 BAGS Thomas B. Ludlow 'and Donovan D. Wendt, St. Paul, Minn., assignors to Bemis Company, Inc., a corporation of Missouri Filed Jan. 28, 1965, Ser. No. 428,697 3 Claims. (Cl. 229-60) This invention relates to bags, and more particularly to bags made of flexible heat-scalable sheet plastic material such as polyethylene.

Among the several objects of this invention may be noted the provision of an open-mouth plastic bag, and particularly a heavy-duty polyethylene lbag for powdered or granular material, which is adapted when filled to square olf, i.e., to have a rectangular top yand bottom, being of such construction that, for a bag of given capacity, substantially less plastic material is needed than for a conventional at-tube bag of the same capacity having conventional end seals (which tis of pillow-form when filled); the provision of :a bag such as described adapted for heat-sealing at its mouth to close the latter after the bag has been lled; and the provision of a bag such as described wherein the bottom yand top closures are heatsealed without any block-ing thereof due to the heat-sealing. Other objects and features will be in part apparent and in .part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafter described, the scope of the invention being indicated in the following claims.

In the accompanying drawings, in which several of various possible embodiments of the invention are illustrated:

FIG. 1 is a view in elevation of one face of a bag tube from which a first form of bag of Ithis invention is made;

FIG. 2 -is a view in elevation of the other face of the FIG. 1 tube;

FIG. 3 is a view showing the inside faces of the Walls of the FIG. 1 tube;

FIG. 4 is a View similar to FIG. 1 showing certain steps in the formation of bottom and top closures for the tube;

FIG. 5 is a view similar to FIG. 4 showing the completed bag;

FIG. 6 is an enlarged section on line 6-6 of FIG. 5;

FIG. 7 is a view in elevation of one face of a bag tube from which a second form of bag of this invention is made;

FIG. 8 is a view in elevation of the other face of the FIG. 7 Itube;

FIG. 9 is a view showing the inside faces of the walls of the FIG. 7 tube;

FIG. 10 is a view similar to FIG. 7 showing certain steps in the formation of 'bottom and top closures for the FIG. 7 tube;

FIG. 11 is a view similar to FIG. 10 showing the completed second form of bag; and

FIG. l2 is an enlarged section on line 12-12 of FIG. 1l.

Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

Referring to the drawings, FIGS. 1 and 2 show a iiat bag t-ube 1 from which a tbag of this invention is made, this tube being made of flexible heat-scalable sheet plastic material such a polyethylene. The opposed walls of the tube are designated 3 and 5. Wall 3 may be referred to Patented August `2, 1966 as the front wall and wall 5 as the back wall. The side folds of the tube, which constitute its side edges, are designated 7 and 9.

At one end of the tube (its bottom end as shown in the drawings), the front wall 3 has a rectangular notch 11 and the back wall 5 has an integral rectangular extension 13. The length ofthis extension (its dimension laterally of the tube) corresponds to the length of the notch (its dimension laterally of the tube), and the projection of the extension from the end ofthe tube corresponds to .the depth of the notch. The back wall 5 has slits 15 extending inward from its bottom end at the ends of the extension 13 a distance corresponding to the depth of the notch.

A=t the other end of the tube (its upper end as shown in the drawings), the front wall 3 has an integral rectangular extension 13a corresponding to the extension 13 with slits 15a cor-responding to slits 15, and the back Wall 5 has a rectangular notch 11a corresponding to notch 11. FIG. 3 `is a developed view of the tube (showing i-t as if it were slit on the edge 7 and unfolded flat) better to illustrate the notch 1-1 in the front wall and the extension 13 of the back wall Vat the bottom, and the notch 11a in the back wall and the extension 13a of the front Wall at the top, and also to -illustrate certain patterns of heat-sealinhibiting material on the inside faces of the tube walls.

It will be understood that bag tubes such as the tube 1 shown in FIGS. l and 2 are manufactured in commercial production by segmenting a continuous length of tubing into individual tubes 1. As to any given tube 1, the provision of notch 11 at the bottom of the front wall and the extension 13 at the bottom of the lback wall provides the notch 11a at the top of the back Wall and the extension 13a at the top of the fr-ont wall of the next adjacent tube segmented from the continuous length of tubing. In other words, as to any given tube 1, the material for extension 13 is cut `out of the adjacent end of the following tube and the material for extension 13a is cut out of the adjacent end of the succeeding tube, thereby also forming the notches 11 and 11a.

Adjacent the bottom end of the tube 1, the front wall 3 has on its inside face a pattern of heat-seal-inhibiting material such as indicated generally at 17. This pattern comprises a stripe 19 of the heat-seal-inhibiting material extending transversely across the inside face of 4the front wall from near one side of the tube to near the other side of the tube adjacent but spaced from the inner edge of the notch 11, and relatively short stripes 21 of heatseal-inhibiting material which extend at an angle of 45 to the stripe 19 adjacent the ends thereof, converging in upward direction. Adjacent the bottom end of the tube, the back Wall has on its inside face two relatively short 45 angled stripes 23 of heat-seal-inhibiting material which register with the 45 angled stripes 21 on the inside face of the front Wall.

Adjacent the upper end of the tube 1, the back wall 5 has on its inside face a pattern 17a of heat-seal-inhibiting material (corresponding to pattern 17) and comprising a stripe 19a extending transversely across the inside face of the back wall from near one side of the tube to near its other side adjacent but spaced from the inner edge of the notch 11a, and relatively short stripes 21a of heat-seal-inhibiting material which extend at an angel of 45 to the stripe 19a adjacent the ends thereof, converging in downward direction. Also, adjacent the upper end of the tube, the front Wall has on its inside face two relatively short 45 angled stripes 23a of heat-seal-inhibiting material which register with the 45 angled stripes 21a on the inside face of the back wall.

The heat-seal-inhibiting material used at 17, 23, 17a and 23a may be, for example, a commercially available polyamide-base ink printed on .the plastic material from which the tube 1 is formed by suitable means. The ink may be unpigmented so as not to appear through the plastic material, which is usually transparent polyethylene. It will be understood that the continuous tubing from which tubes 1 are .segmented may be made from flat web stock which is printed on one face with the heat-seal-inhibiting material at 17, 23, 17a and 23a at appropriate intervals along its length prior to being formed into the continuous tubing (the printed face of the web coming on the inside of the tubing). In such case the tubing and the tubes 1 into which the tubing is segmented have a longitudinal seam indicated -at S in the back wall (a so-called back seam).

The'tube 1 is provided with a diamond-fold bottom closure as shown in FIGS. 4-6 by opening up the bottom end of the tube and folding back a bottom end portion 27 of the front wall on a fold line 29 extending transversely across the tube at the inner ends of the 45 angled stripes 21. This operation results in the formation of end flaps 31 and a main bottom flap 33 (constituted by a bottom end portion of the back wall 5) for the diamond-fold closure. Line 29 and the inner ends of stripes 21 are spaced from the inner edge 34 of the notch (i.e., the edge of the notch which extends transversely of the tube) a distance somewhat greater than half the width of the ultimate damond-fold closure and line 29 and the outer edge E of stripe 19 are spaced a distance generally equal to half the width of the ultimate diamondfold closure. Each of the end flaps 31 has a triangular portion 35 having an apex 37 at the respective end of the fold line 29, the sides of triangular portion 35' being constituted by a fold on a 45 line 39 extending from the apex 37 to the adjacent corner 41 of the notch 11 and a fold on a 45 line 43- extending from the apex 37 to the inner end of the adjacent slit 15 in the back wall 5. Stripe 19 terminates generally at fold lines 39, its ends 45 being angled at 45 in accordance with the 45 angle of fold lines 39. Each end ap 3-1 also has a rectangular extension 47 -at its inner end, one side edge 49 of which is defined by the respective end of notch 11 and the other side edge 51 of which is dened by the respective slit 15.

In the condition of the tube 1 as shown in FIG. 4 with the bottom end opened up to form the inwardly directed end aps 31 of the diamond-fold bottom closure, the bottom end portion 27 of the front wall 3 is laid back on the outside of the front Wall 3 of the tube. The stripe 19 of heat-seal-inhibiting material extends across the outer face of this bottom end portion 27 of the front wall from one fold line 39 to the other fold line 39, the end portions of stripe 19 lying underneath the end aps 31. Stripe 19 is spaced from edge 34 of portion 27. Stripes 21 extend at 45 angles from the ends of stripe 19 (at right angles to fold lines 39) to the fold line 29. Stripes 23 extend from fold lines 43 at right angles thereto to a meeting with the inner ends of stripes 21.

Following the above, the Ymain bottom flap 33 is folded over on a transverse fold line 53 parallel t-o line 29 to o verlie the end iiaps 31 and part of portion 27. This line 53 extends generally between the outer ends of stripes 23. The distance from line 29 to the outer edge 55 of flap '33 is generally equal to one and one-half time-s the width of the ultimate diamond-fold closure, and line 53 is spaced from line 29 one-half the width of the ultimate diamond-fold closure. Accordingly, when flap 33 is folded over on line 53, its outer edge 55 is brought generally int-o register with `the outer edge E of stripe 19.V

This Ileaves a lip 57 on portion 27 lying outward beyond edge E of stripe 19. This l-ip 57 is folded around the edge A5'5 of flap 33 on a fold line 59 to overlie the ap 33, and is then heat-sealed to flap 33 along a line 61 extending across the bott-om formation lying within the confines of stripe 19 (see FIGS. 5 'and 6). Heat seals are made on lines 63 extending at 45 angles from the ends of line 59 within the confines of stripes 21 and heat seals are made on lines 6'5 extending at 45 angles from the ends of line 53 within the contines of stripe V23 to secure the folded-over main bottom flap 33 to the end aps 31 thereby to complete the formation of the bottom closure. The latter is designated 67 in FIGS. 5 and 6. It will be observed that the seals may be made at 61, 63 and `65 without blocking of the bottom closure (i.e., without any heat-sealing together of the opposed faces of flap 33 and portion 27 along line 61 and without any heat-sealing together of the opposed faces of the end flaps 31 and bottom end portion 27 of the front wall 3 and flap 33 along lines 63 and 65) because of the interposition between these opposing farces of the heatfsealinhibiting material at 19, 21 and 23 where the seals are made at 61, 63 and 65.

The tube 1 is provided with a diamond-fold openmouth top formation as shown in FIGS. 4 and 5 which i s similar to the diamond-fold bottom closure, except that the seal at 61 lis initially omitted so that the bag, as supplied by the bag manufacturer, has what amounts to an open mouth. Parts of the top formation corresponding to those of the bottom closure are identified :by the same reference characters as used to identify the parts of the bottom closure with the adjunct a on each reference character applied to the top formation. As will appear best from FIG. 4, another difference between the bottom closure and the top formation is that the top is opened up by folding back the upper end portion of the front wall. However, the bottom closure andthe top formation, as will appear from FIGS. 4 and 5, are essentially the same except that lip 57a of the top formation is not initially folded over and sealed so as to leave an open mouth at 69 between portion 27a and flap 33 at the top of the bag. After the bag has been filled through the mouth 69, the lip 57a may be folded over and sealed by a seal the same as at 61, with the heat-seal-inhibiting material at 19a preventing blocking. The completed top .formation is designated 71 in FIG. 5. When the bag is filled, and the top formation is sealed to close the mouth 69, the bottom and top closures square out, i.e., they assume a rectangular form, -the long sides of the resultant rectangular bottom formation being the fold lines 53 and 59, and the long sides of the resultant rectangular top formation being the fold lines 53a and 59a.

In the bag shown in FIGS. 1-6 and described above, the main bottom flap 33 is part of the initially unfolded bottom end portion of the back wall and the main top flap 33a is part of the folded-back en portion of the front wall. Lips '57 and 67a are integral portions of the end portions 27 and 27a. FIGS. 7-12 illustrate a modification in -Whi'ch the main -bottom fla'p is part of a folded-back end portion of the front wall and the main top ap is part of an initially unfolded end portion of the back Wall (the reverse of FIGS. 4 and 5), and in which the lips are constituted by a separate length of tape of heat-sealable sheet plastic material (c g., polyethylene).

Referring to FIGS. 7-9, there is shown a flat bag tube 101 made of flexible heat-scalable sheet plastic material such as polyethylene. The front and lback walls of this tube are designated 103 and `105 and its side edges are designated 107 and 109. At the bottom end of the tube, the back wall has a rectangular notch 111 and the front wall has an integral rectangular extension 113, with slits at the ends of the extension. At the top end of the tube, the front Wall 103. has a notch 111,@

and the back Wall has an integral rectangular extension 113a, with slits 1115a corresponding to slits 115 at the ends of the extension. Adjacent lthe bottom end of the tube, the back wall 105 has on its inside face a pattern 117 of heat-seal-inhi-biting material which is similar to pattern 17 except that the transverse stripe `119 of the pattern 117 is contiguous to the inner edge of notch 111, The 45 angled stripes of the pattern 4117 are designated 121. The front -Wall has short stripes 123 on its inside face similar to strips 23. Adjacent the upper end of the tube, a front wall 1103 has on its inside face a pattern 117a of heat-seal-inhibit-ing material which is similar to pattern 17a except that the transverse stripe 11911l of the the pattern 117:1 is contiguous `to the inner edge of notch 111a. The 45 angled stripes of the pattern 117a are designated 121a, and the back Wall has short stripes 123a similar to stripes 23a.

As shown in FIGS. yand 11, the tube 101 is provided with a diamond-fold bottom closure by opening up the bottom end of the tube and folding back a bottom end portion 127 of the front wall on a fold line 129 extending across the tube at the inner end of stripes 123. This results in the formation of end aps 131 (corresponding to end flaps 31). A section of the folded-back portion constitutes the main bottom flap 133 for the diamond-fold closure. Line 129 and the inner ends of stripes 121 are spaced from the inner edge 134 of notch 111 a distance corresponding generally to half the width of the ultimate diamond-fold closure. Each of the end flaps 131 has a triangular portion 135 having an apex 137 at the respective end of the fold line 129, the sides of the triangular portion 135 being constituted by a fold on a 45 line 139 extending from apex 137 to the adjacent corner 141 of the notch 111 and a fold on a 45 line 143 extending from the apex 137 to the inner end of the adjacent slit in th'e front Wall 103. Stripe 119 terminates generally at fold lines 139, its ends 145 being angled at 45 in accordance With the 45 angle of fold Ilines 139. Each end flap also has a rectangular extension 147 at its inner end, one side edge 149 0f which is defined by the respective end of notch 111 and the other sid'e edge 151 of which is defined by the respective slit 115.

Following the above, the main bottom ap 133 is folded over on a transvers fold line 153 parallel to line 129 to overlie the end flaps 131. The distance from line 129 to the upper edge 155 of portion 127 and the location of line 153 are lsuch that, when ap 133 is folded over on line 153, edge 155 is brought generally into register Wit-h the edge 134. Then, a length of tape 157 of heat-sealable sheet plastic material is folded around the edges 134 and 155. The fold of the tape is designated 159. A heat seal is made on line 161 extending across the tape, resulting in heat-sealing of the flap and tape at 161a as shown in FIG. 12 and of lthe bottom end portion of the back wall 105 and the tape at 161b, without sealing of the flap and the bottom end portion of the back wall 105 by reason of the stripe 119 of heatseal-inhibiting material. Heat seals are also made on lines 163 and 165 (corresponding to lines 63 and 65) to complete the formation of the bottom closure lwhich is designated 167 in FIGS. l1 and 12.

The tube 101 is provided with a diamond-fold openmouth formation as shown in FIGS. 10 and 11 which is similar to its diamond-fold bottom closure, except that the tape 157 is initially omitted so that the bag, as supplied by the bag manufacturer, has an open mouth at 169. Parts of the top formation corresponding to those of the bottom closure are identified by the same reference characters as used to identify the parts of the bottom closure with the adjunct a on each reference character applied to the top formation. It will be understood that after the bag has been filled through the mouth at 169, the mouth may be closed by a tape the same as 157.

The completed top formation is designated 171 in FIG. 11.

Each of the forms of bag shown in FIGS. 5 and 11 is of such construction that, for a bag of given capacity, substantially less plastic material is needed than for a flat-tube bag with conventional end seals that assumes a pillow-form when filled. Thus, for example, a bag of this invention made from a tube initially about seventeen inches wide (in the at) and about twenty-five inches long contains as much as a flat-tube bag with conventional end seals some two inches longer.

It will be understood that the pattern of heat-seal-inhibiting material at the ends of the tube may be widely varied from the patterns specifically shown herein, the principal criteria being that they inhibit blocking of the top and bottom closures.

In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

As various changes could be made in the above cons-tructions Without departing from the scope of the invention, it is intended that all matter container in the above description or shown in the accompanying drawings shaltl be interpreted as illustrative and not in a limiting sense.

Wha-t is claimed is:

1. An open-mouth plastic bag adapted when filled to have a rectangular bottom and a rectangular top, said bag being formed from a fiat tube of heat-sealable sheet plastic material and having a bottom closure formation at one end thereof and a top closure formation at the other end, each of said closure formations comprising a folded-back end portion of one of the walls of the tube whi-ch is folded over on the outside of said one wall on a iirst fold line extending transversely across said one wall, an unfolded end portion of the other wall of the tube extending outward beyond said first fold line oppositely to said folded-back end portion, and inwardly directed end aps at the corners of the tube, each end flap having a triangular portion with its apex at a respective end of said first fold line, a part of one of said end portions constituting a main closure flap which is folded back on a second fold line extending parallel to said first fold line and spaced therefrom half the width of the closure formation to overlie the end flaps and the other of said end portions, said second fold line `defining one side of the closure formation and said flap extending therefrom to the other side of the closure formation, each of said closure formations having heat seals securing the main ap thereof to the respective end flaps, the main Hap of the bottom closure formation being joined to the respective other of said end portions along the said other side of the bottom closure formation by a 4lip of plastic material extending from one end portion around the edge of the other end portion and lying on the outside of the latter, and a heat seal for the lip along a line extending adjacent said other side of the bottom closure formation from one end flap to the other, the main ap of the top closure formation being initially free of the respective other of said end portions along the said other side of the top closure formation to provide an open mouth and adapted, after filling of the bag, to be joined to the respective other of said end portions by a lip of plastic material and a heat seal lfor the lip along a line extending adjacent said other side of the top closure formation from one end flap to the other, a stripe of heat-seal-inhibiting material extending across one of said end portions of the bottom closure formation between the end portions of the bottom closure formation along the line of the heat seal for the lip of the bot tom closure formation and inhibiting blocking of the bottom closure formation along the heat seal for the lip thereof, and a stripe of heat-seal-inhibiting material extending across one of said end portions of the top closure formation between the end portions of the top closure 7 formation along the line of the heat seal for .the lip of the top closure formation to inhibit blocking of the top closure formation along the subsequently made heat seal -for the lip thereof.

2. An open-mouth plastic bag as set forth in claim 1 wherein each said lip is an integral part of one of said end portions.

3. An open-mouth plastic bag as set forth in claim 1 wherein said lip is `constituted by a heat-sealable tape of said end portions.

References Cited bythe Examiner UNITED STATES PATENTS Waters 229-57 Crawford et al. 229-17 Camerini 229-53 Symons et al. a- 229-625 JOSEPH R. LECLAIR, Primary Examiner. folded around the edges of the main ap and the other 10 D, M BOCKENEKs Assistant Examiner, 

1. AN OPEN-MOUTH PLASTIC BAG ADAPTED WHEN FILLED TO HAVE A RECTANGULAR BOTTOM AND A RECTANGULAR TOP, SAID BAG BEING FORMED FROM A FLAT TUBE OF HEAT-SEALABLE SHEET PLASTIC MATERIAL AND HAVING A BOTTOM CLOSURE FORMATION AT ONE END THEREOF AND TOP CLOSURE FORMATION AT THE OTHER END, EACH OF SAID CLOSURE FORMATIONS COMPRISING A FOLDED-BACK END PORTION OF ONE OF THE WALLS OF THE TUBE WHICH IS FOLDED OVER ON THE OUTSIDE OF SAID ONE WALL ON A FIRST FOLD LINE EXTENDING TRANSVERSELY ACROSS SAID ONE WALL, AN UNFOLDED END PORTION OF THE OTHER WALL OF THE TUBE EXTENDING OUTWARD BEYOND SAID FIRST FOLD LINE OPPOSITELY TO SAID FOLDED-BACK END PORTION, AND INWARDLY DIRECTED END FLAPS AT THE CORNERS OF THE TUBE, EACH END FLAP HAVING A TRIANGULAR PORTION WITH ITS APEX AT A RESPECTIVE END OF SAID FIRST FOLD LINE, A PART OF ONE OF SAID END PORTIONS CONSTITUTING A MAIN CLOSURE FLAP WHICH IS FOLDED BACK ON A SECOND FOLD LINE EXTENDING PARALLEL TO SAID FIRST FOLD LINE AND SPACED THEREFROM HALF THE WIDTH OF THE CLOSURE FORMATION TO OVERLIE THE END FLAPS AND THE OTHER OF SAID END PORTIONS, SAID SECOND FOLD LINE DEFINING ONE SIDE OF THE CLOSURE FORMATION AND SAID FLAP EXTENDING THEREFROM TO THE OTHER SIDE OF THE CLOSURE FORMATION, EACH OF SAID CLOSURE FORMATIONS HAVING HEAT SEALS SECURING THE MAIN FLAP THEREOF TO THE RESPECTIVE END FLAPS, THE MAIN FLAP OF THE BOTTOM CLOSURE FORMATION BEING JOINED TO THE RESPECTIVE OTHER OF SAID END PORTIONS ALONG THE SAID OTHER SIDE OF THE BOTTOM CLOSURE FORMATION BY A LIP OF PLASTIC MATERIAL EXTENDING FROM ONE END PORTION AROUND THE EDGE OF THE OTHER END PORTION AND LYING ON THE OUTSIDE OF THE LATTER, AND AT HEAT SEAL FOR THE LIP ALONG A LINE EXTENDING ADJACENT SAID OTHER SIDE OF THE BOTTOM CLOSURE FORMATION FROM ONE END FLAP TO THE OTHER, THE MAIN FLAP OF THE TOP CLOSURE FORMATION BEING INITIALLY FREE OF THE RESPECTIVE OTHER OF SAID END PORTIONS ALONG THE SAID OTHER SIDE OF THE TOP CLOSURE FORMATION TO PROVIDE AN OPEN MOUTH AND ADAPTED, AFTER FILLING OF THE BAG, TO BE JOINED TO THE RESPECTIVE OTHER OF SAID END PORTIONS BY A LIP OF PLASTIC MATERIAL AND A HEAT SEAL FOR THE LIP ALONG A LINE EXTENDING ADJACENT SAID OTHER SIDE OF THE TOP CLOSURE FORMATION FROM ONE END FLAP TO THE OTHER, A STRIPE OF HEAT-SEAL-INHIBITING MATERIAL EXTENDING ACROSS ONE OF SAID END PORTIONS OF THE BOTTOM CLOSURE FORMATION BETWEEN THE END PORTIONS OF THE BOTTOM CLOSURE FORMATION ALONG THE LINE OF THE HEAT SEAL FOR THE LIP OF THE BOTTOM CLOSURE FORMATION AND INHIBITING BLOCKING OF THE BOTTOM CLOSURE FORMATION ALONG THE HEAT SEAL FOR THE LIP THEREOF, AND A STRIPE OF HEAT-SEAL-INHIBITING MATERIAL EXTENDING ACROSS ONE OF SAID END PORTIONS OF THE TOP CLOSURE FORMATION BETWEEN THE END PORTIONS OF THE TOP CLOSURE FORMATION ALONG THE LINE OF THE HEAT SEAL FOR THE LIP OF THE TOP CLOSURE FORMATION TO INHIBIT BLOCKING OF THE TOP CLOSURE FORMATION ALONG THE SUBSEQUENTLY MADE HEAT SEAL FOR THE LIP THEREOF. 